Allowable stress for ductile iron
Allowable stress for ductile iron
(OP)
Hi, I am currently attempting to design a ductile iron pump casing using Sec. VIII div 2 and have found that ductile iron maximum allowable stresses are not found under Table 5A in Sec. II-D and only under Table 2A for Design Stress Intensity which I understand should only be used when designing to Section III Classes 1, Tc, and SC. I understand the values of stresses in each table are based on different theories of failure and design margins, and are not interchangeable.
So, I suppose my question is, does this mean it is not suitable to design a ductile iron pressure vessel to Sec VIII div 2, and if so (which I'm guessing is the case) why is that? Just because of the failure theory associated with that section of code? Any insight and further detail is much appreciated. Thanks.
So, I suppose my question is, does this mean it is not suitable to design a ductile iron pressure vessel to Sec VIII div 2, and if so (which I'm guessing is the case) why is that? Just because of the failure theory associated with that section of code? Any insight and further detail is much appreciated. Thanks.





RE: Allowable stress for ductile iron
RE: Allowable stress for ductile iron
Send a letter to the committee, but first check old code case lists, see if it has been asked before.
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P.E. Metallurgy, Plymouth Tube
RE: Allowable stress for ductile iron
RE: Allowable stress for ductile iron
I know the BPV code isn't directly applicable for use on a pump, however sometimes customers request we do so, and so we do.
Can you shed some more light as to why raising this question would be considered consulting? I understand why gray cast iron would provide concern for use in a pressure containing device, however ductile iron should alleviate most of those or maybe I am just missing something obvious...
RE: Allowable stress for ductile iron
"The specifications speak for themselves".......
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P.E. Metallurgy, Plymouth Tube